Fix handling of yychar manipulation in user semantic actions.

The problem was that yacc.c didn't always update the yychar
translation afterwards.  However, other skeletons appear to be
fine.  glr.c appears to already translate yychar before every
use.  lalr1.cc does not define yychar and does not document its
replacement, yyla, for users.  It does provide yyclearin, but
that does not manipulate yyla and thus requires no translation
update.  In lalr1.java, yychar is out of scope during semantic
actions.
* NEWS (2.5): Document.
* data/yacc.c (YYBACKUP): Don't bother translating yychar into
yytoken here.
(yyparse, yypush_parse): Instead, translate before every use of
yytoken, and add comments explaining this approach.
* tests/actions.at (Destroying lookahead assigned by semantic
action): New test group checking that translation happens before
lookahead destructor calls at parser return.  Previously,
incorrect destructors were called.
* tests/conflicts.at (parse.error=verbose and consistent
errors): New test group checking that translation happens at
syntax error detection before the associated verbose error
message and the associated lookahead destructor calls.  While
the destructor call is fixed by this patch, the verbose error
message is currently incorrect due to another bug (see
comments in test group), so this is an expected failure for now.

diff --git a/ChangeLog b/ChangeLog
index d0e6d792d9d003e6c1957b8fd3f36605084bfa3a..5b3011e561773c09173a508c3cf963d2138996f6 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,31 @@
+2009-12-20  Joel E. Denny  <jdenny@clemson.edu>
+
+       Fix handling of yychar manipulation in user semantic actions.
+       The problem was that yacc.c didn't always update the yychar
+       translation afterwards.  However, other skeletons appear to be
+       fine.  glr.c appears to already translate yychar before every
+       use.  lalr1.cc does not define yychar and does not document its
+       replacement, yyla, for users.  It does provide yyclearin, but
+       that does not manipulate yyla and thus requires no translation
+       update.  In lalr1.java, yychar is out of scope during semantic
+       actions.
+       * NEWS (2.5): Document.
+       * data/yacc.c (YYBACKUP): Don't bother translating yychar into
+       yytoken here.
+       (yyparse, yypush_parse): Instead, translate before every use of
+       yytoken, and add comments explaining this approach.
+       * tests/actions.at (Destroying lookahead assigned by semantic
+       action): New test group checking that translation happens before
+       lookahead destructor calls at parser return.  Previously,
+       incorrect destructors were called.
+       * tests/conflicts.at (parse.error=verbose and consistent
+       errors): New test group checking that translation happens at
+       syntax error detection before the associated verbose error
+       message and the associated lookahead destructor calls.  While
+       the destructor call is fixed by this patch, the verbose error
+       message is currently incorrect due to another bug (see
+       comments in test group), so this is an expected failure for now.
+
 2009-12-21  Joel E. Denny  <jdenny@clemson.edu>
 
        YYFAIL: warn about uses and remove from lalr1.java.

diff --git a/NEWS b/NEWS
index b704ed528bfd0095d257f065e92a54f8d50219dd..09610cbf5c19c5aa0e3aba8da44dd33a300fc92e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -223,6 +223,13 @@ Bison News
   were resolved with %nonassoc.  Such tokens are now properly omitted
   from the list.
 
+** Destructor calls fixed for lookaheads altered in semantic actions.
+
+  Previously for deterministic parsers in C, if a user semantic action
+  altered yychar, the parser in some cases used the old yychar value to
+  determine which destructor to call for the lookahead upon a syntax
+  error or upon parser return.  This bug has been fixed.
+
 * Changes in version 2.4.2 (????-??-??):
 
 ** Detection of GNU M4 1.4.6 or newer during configure is improved.

diff --git a/data/yacc.c b/data/yacc.c
index 5e7b55fc31e4af09232d323ca1e658db24c3d5ef..462b8526678606a02511170fa18aaffcaa2809fe 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -630,7 +630,6 @@ do                                                          \
     {                                                          \
       yychar = (Token);                                                \
       yylval = (Value);                                                \
-      yytoken = YYTRANSLATE (yychar);                          \
       YYPOPSTACK (1);                                          \
       goto yybackup;                                           \
     }                                                          \
@@ -1429,6 +1428,17 @@ yyreduce:
       ]b4_user_actions[
       default: break;
     }
+  /* User semantic actions sometimes alter yychar, and that requires
+     that yytoken be updated with the new translation.  We take the
+     approach of translating immediately before every use of yytoken.
+     One alternative is translating here after every semantic action,
+     but that translation would be missed if the semantic action invokes
+     YYABORT, YYACCEPT, or YYERROR immediately after altering yychar or
+     if it invokes YYBACKUP.  In the case of YYABORT or YYACCEPT, an
+     incorrect destructor might then be invoked immediately.  In the
+     case of YYERROR or YYBACKUP, subsequent parser actions might lead
+     to an incorrect destructor call or verbose syntax error message
+     before the lookahead is translated.  */
   YY_SYMBOL_PRINT ("-> $$ =", yyr1[yyn], &yyval, &yyloc);
 
   YYPOPSTACK (yylen);
@@ -1457,6 +1467,10 @@ yyreduce:
 | yyerrlab -- here on detecting error |
 `------------------------------------*/
 yyerrlab:
+  /* Make sure we have latest lookahead translation.  See comments at
+     user semantic actions for why this is necessary.  */
+  yytoken = YYTRANSLATE (yychar);
+
   /* If not already recovering from an error, report this error.  */
   if (!yyerrstatus)
     {
@@ -1609,8 +1623,13 @@ yyexhaustedlab:
 
 yyreturn:
   if (yychar != YYEMPTY)
-     yydestruct ("Cleanup: discarding lookahead",
-                yytoken, &yylval]b4_locations_if([, &yylloc])[]b4_user_args[);
+    {
+      /* Make sure we have latest lookahead translation.  See comments at
+         user semantic actions for why this is necessary.  */
+      yytoken = YYTRANSLATE (yychar);
+      yydestruct ("Cleanup: discarding lookahead",
+                  yytoken, &yylval]b4_locations_if([, &yylloc])[]b4_user_args[);
+    }
   /* Do not reclaim the symbols of the rule which action triggered
      this YYABORT or YYACCEPT.  */
   YYPOPSTACK (yylen);

diff --git a/src/parse-gram.c b/src/parse-gram.c
index 03495f6deb2eec156c7446e82ce6a7a21076d79a..a572fbab6067d8ef8102d3f15b801d6420ea0664 100644 (file)
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 2.4.456-ea2e.  */
+/* A Bison parser, made by GNU Bison 2.4.457-4395a.  */
 
 /* Implementation for Bison's Yacc-like parsers in C
 
@@ -45,7 +45,7 @@
 #define YYBISON 1
 
 /* Bison version.  */
-#define YYBISON_VERSION "2.4.456-ea2e"
+#define YYBISON_VERSION "2.4.457-4395a"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -906,7 +906,6 @@ do                                                          \
     {                                                          \
       yychar = (Token);                                                \
       yylval = (Value);                                                \
-      yytoken = YYTRANSLATE (yychar);                          \
       YYPOPSTACK (1);                                          \
       goto yybackup;                                           \
     }                                                          \
@@ -1029,106 +1028,106 @@ yy_symbol_value_print (yyoutput, yytype, yyvaluep, yylocationp)
     {
             case 3: // "string"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 175 "src/parse-gram.y"
         { fputs (quotearg_style (c_quoting_style, ((*yyvaluep).chars)), stderr); }
-/* Line 731 of yacc.c  */
-#line 1037 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1036 "src/parse-gram.c"
         break;
 
             case 4: // "integer"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 188 "src/parse-gram.y"
         { fprintf (stderr, "%d", ((*yyvaluep).integer)); }
-/* Line 731 of yacc.c  */
-#line 1046 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1045 "src/parse-gram.c"
         break;
 
             case 24: // "%<flag>"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 184 "src/parse-gram.y"
         { fprintf (stderr, "%%%s", ((*yyvaluep).uniqstr)); }
-/* Line 731 of yacc.c  */
-#line 1055 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1054 "src/parse-gram.c"
         break;
 
             case 40: // "{...}"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 177 "src/parse-gram.y"
         { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).code)); }
-/* Line 731 of yacc.c  */
-#line 1064 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1063 "src/parse-gram.c"
         break;
 
             case 41: // "[identifier]"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 182 "src/parse-gram.y"
         { fprintf (stderr, "[%s]", ((*yyvaluep).uniqstr)); }
-/* Line 731 of yacc.c  */
-#line 1073 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1072 "src/parse-gram.c"
         break;
 
             case 42: // "char"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 169 "src/parse-gram.y"
         { fputs (char_name (((*yyvaluep).character)), stderr); }
-/* Line 731 of yacc.c  */
-#line 1082 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1081 "src/parse-gram.c"
         break;
 
             case 43: // "epilogue"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 177 "src/parse-gram.y"
         { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
-/* Line 731 of yacc.c  */
-#line 1091 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1090 "src/parse-gram.c"
         break;
 
             case 45: // "identifier"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 181 "src/parse-gram.y"
         { fputs (((*yyvaluep).uniqstr), stderr); }
-/* Line 731 of yacc.c  */
-#line 1100 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1099 "src/parse-gram.c"
         break;
 
             case 46: // "identifier:"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 183 "src/parse-gram.y"
         { fprintf (stderr, "%s:", ((*yyvaluep).uniqstr)); }
-/* Line 731 of yacc.c  */
-#line 1109 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1108 "src/parse-gram.c"
         break;
 
             case 49: // "%{...%}"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 177 "src/parse-gram.y"
         { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
-/* Line 731 of yacc.c  */
-#line 1118 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1117 "src/parse-gram.c"
         break;
 
             case 51: // "<tag>"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 185 "src/parse-gram.y"
         { fprintf (stderr, "<%s>", ((*yyvaluep).uniqstr)); }
-/* Line 731 of yacc.c  */
-#line 1127 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1126 "src/parse-gram.c"
         break;
 
             case 54: // "%param"
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 231 "src/parse-gram.y"
         {
   switch (((*yyvaluep).param))
@@ -1142,80 +1141,80 @@ yy_symbol_value_print (yyoutput, yytype, yyvaluep, yylocationp)
       case param_none: aver (false); break;
     }
 }
-/* Line 731 of yacc.c  */
-#line 1147 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1146 "src/parse-gram.c"
         break;
 
             case 71: // symbol.prec
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 191 "src/parse-gram.y"
         { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
-/* Line 731 of yacc.c  */
-#line 1156 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1155 "src/parse-gram.c"
         break;
 
             case 84: // variable
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 181 "src/parse-gram.y"
         { fputs (((*yyvaluep).uniqstr), stderr); }
-/* Line 731 of yacc.c  */
-#line 1165 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1164 "src/parse-gram.c"
         break;
 
             case 85: // content.opt
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 177 "src/parse-gram.y"
         { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
-/* Line 731 of yacc.c  */
-#line 1174 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1173 "src/parse-gram.c"
         break;
 
             case 86: // braceless
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 177 "src/parse-gram.y"
         { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
-/* Line 731 of yacc.c  */
-#line 1183 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1182 "src/parse-gram.c"
         break;
 
             case 87: // id
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 191 "src/parse-gram.y"
         { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
-/* Line 731 of yacc.c  */
-#line 1192 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1191 "src/parse-gram.c"
         break;
 
             case 88: // id_colon
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 192 "src/parse-gram.y"
         { fprintf (stderr, "%s:", ((*yyvaluep).symbol)->tag); }
-/* Line 731 of yacc.c  */
-#line 1201 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1200 "src/parse-gram.c"
         break;
 
             case 89: // symbol
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 191 "src/parse-gram.y"
         { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
-/* Line 731 of yacc.c  */
-#line 1210 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1209 "src/parse-gram.c"
         break;
 
             case 90: // string_as_id
 
-/* Line 731 of yacc.c  */
+/* Line 730 of yacc.c  */
 #line 191 "src/parse-gram.y"
         { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
-/* Line 731 of yacc.c  */
-#line 1219 "src/parse-gram.c"
+/* Line 730 of yacc.c  */
+#line 1218 "src/parse-gram.c"
         break;
 
       default:
@@ -1745,7 +1744,7 @@ YYLTYPE yylloc;
 #endif
 
 /* User initialization code.  */
-/* Line 1216 of yacc.c  */
+/* Line 1215 of yacc.c  */
 #line 80 "src/parse-gram.y"
 {
   /* Bison's grammar can initial empty locations, hence a default
@@ -1753,8 +1752,8 @@ YYLTYPE yylloc;
   boundary_set (&yylloc.start, current_file, 1, 1);
   boundary_set (&yylloc.end, current_file, 1, 1);
 }
-/* Line 1216 of yacc.c  */
-#line 1758 "src/parse-gram.c"
+/* Line 1215 of yacc.c  */
+#line 1757 "src/parse-gram.c"
   yylsp[0] = yylloc;
 
   goto yysetstate;
@@ -1940,7 +1939,7 @@ yyreduce:
   switch (yyn)
     {
         case 6:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 267 "src/parse-gram.y"
     {
       code_props plain_code;
@@ -1951,106 +1950,106 @@ yyreduce:
                         plain_code.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 1956 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 1955 "src/parse-gram.c"
     break;
 
   case 7:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 277 "src/parse-gram.y"
     {
       muscle_percent_define_ensure ((yyvsp[0].uniqstr), (yylsp[0]), true);
     }
-/* Line 1429 of yacc.c  */
-#line 1966 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 1965 "src/parse-gram.c"
     break;
 
   case 8:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 281 "src/parse-gram.y"
     {
       muscle_percent_define_insert ((yyvsp[-1].uniqstr), (yylsp[-1]), (yyvsp[0].chars),
                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
     }
-/* Line 1429 of yacc.c  */
-#line 1977 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 1976 "src/parse-gram.c"
     break;
 
   case 9:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 285 "src/parse-gram.y"
     { defines_flag = true; }
-/* Line 1429 of yacc.c  */
-#line 1985 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 1984 "src/parse-gram.c"
     break;
 
   case 10:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 287 "src/parse-gram.y"
     {
       defines_flag = true;
       spec_defines_file = xstrdup ((yyvsp[0].chars));
     }
-/* Line 1429 of yacc.c  */
-#line 1996 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 1995 "src/parse-gram.c"
     break;
 
   case 11:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 292 "src/parse-gram.y"
     {
       muscle_percent_define_insert ("parse.error", (yylsp[0]), "verbose",
                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
     }
-/* Line 1429 of yacc.c  */
-#line 2007 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2006 "src/parse-gram.c"
     break;
 
   case 12:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 296 "src/parse-gram.y"
     { expected_sr_conflicts = (yyvsp[0].integer); }
-/* Line 1429 of yacc.c  */
-#line 2015 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2014 "src/parse-gram.c"
     break;
 
   case 13:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 297 "src/parse-gram.y"
     { expected_rr_conflicts = (yyvsp[0].integer); }
-/* Line 1429 of yacc.c  */
-#line 2023 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2022 "src/parse-gram.c"
     break;
 
   case 14:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 298 "src/parse-gram.y"
     { spec_file_prefix = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2031 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2030 "src/parse-gram.c"
     break;
 
   case 15:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 299 "src/parse-gram.y"
     { spec_file_prefix = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2039 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2038 "src/parse-gram.c"
     break;
 
   case 16:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 301 "src/parse-gram.y"
     {
       nondeterministic_parser = true;
       glr_parser = true;
     }
-/* Line 1429 of yacc.c  */
-#line 2050 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2049 "src/parse-gram.c"
     break;
 
   case 17:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 306 "src/parse-gram.y"
     {
       code_props action;
@@ -2060,92 +2059,92 @@ yyreduce:
       muscle_code_grow ("initial_action", action.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 2065 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2064 "src/parse-gram.c"
     break;
 
   case 18:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 314 "src/parse-gram.y"
     { language_argmatch ((yyvsp[0].chars), grammar_prio, (yylsp[-1])); }
-/* Line 1429 of yacc.c  */
-#line 2073 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2072 "src/parse-gram.c"
     break;
 
   case 19:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 315 "src/parse-gram.y"
     { spec_name_prefix = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2081 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2080 "src/parse-gram.c"
     break;
 
   case 20:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 316 "src/parse-gram.y"
     { spec_name_prefix = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2089 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2088 "src/parse-gram.c"
     break;
 
   case 21:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 317 "src/parse-gram.y"
     { no_lines_flag = true; }
-/* Line 1429 of yacc.c  */
-#line 2097 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2096 "src/parse-gram.c"
     break;
 
   case 22:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 318 "src/parse-gram.y"
     { nondeterministic_parser = true; }
-/* Line 1429 of yacc.c  */
-#line 2105 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2104 "src/parse-gram.c"
     break;
 
   case 23:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 319 "src/parse-gram.y"
     { spec_outfile = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2113 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2112 "src/parse-gram.c"
     break;
 
   case 24:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 320 "src/parse-gram.y"
     { spec_outfile = (yyvsp[0].chars); }
-/* Line 1429 of yacc.c  */
-#line 2121 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2120 "src/parse-gram.c"
     break;
 
   case 25:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 321 "src/parse-gram.y"
     { current_param = (yyvsp[0].param); }
-/* Line 1429 of yacc.c  */
-#line 2129 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2128 "src/parse-gram.c"
     break;
 
   case 26:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 321 "src/parse-gram.y"
     { current_param = param_none; }
-/* Line 1429 of yacc.c  */
-#line 2137 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2136 "src/parse-gram.c"
     break;
 
   case 27:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 322 "src/parse-gram.y"
     { version_check (&(yylsp[0]), (yyvsp[0].chars)); }
-/* Line 1429 of yacc.c  */
-#line 2145 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2144 "src/parse-gram.c"
     break;
 
   case 28:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 324 "src/parse-gram.y"
     {
       char const *skeleton_user = (yyvsp[0].chars);
@@ -2170,62 +2169,62 @@ yyreduce:
         }
       skeleton_arg (skeleton_user, grammar_prio, (yylsp[-1]));
     }
-/* Line 1429 of yacc.c  */
-#line 2175 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2174 "src/parse-gram.c"
     break;
 
   case 29:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 347 "src/parse-gram.y"
     { token_table_flag = true; }
-/* Line 1429 of yacc.c  */
-#line 2183 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2182 "src/parse-gram.c"
     break;
 
   case 30:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 348 "src/parse-gram.y"
     { report_flag |= report_states; }
-/* Line 1429 of yacc.c  */
-#line 2191 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2190 "src/parse-gram.c"
     break;
 
   case 31:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 349 "src/parse-gram.y"
     { yacc_flag = true; }
-/* Line 1429 of yacc.c  */
-#line 2199 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2198 "src/parse-gram.c"
     break;
 
   case 33:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 354 "src/parse-gram.y"
     { add_param (current_param, (yyvsp[0].code), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2207 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2206 "src/parse-gram.c"
     break;
 
   case 34:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 355 "src/parse-gram.y"
     { add_param (current_param, (yyvsp[0].code), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2215 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2214 "src/parse-gram.c"
     break;
 
   case 37:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 367 "src/parse-gram.y"
     {
       grammar_start_symbol_set ((yyvsp[0].symbol), (yylsp[0]));
     }
-/* Line 1429 of yacc.c  */
-#line 2225 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2224 "src/parse-gram.c"
     break;
 
   case 38:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 371 "src/parse-gram.y"
     {
       symbol_list *list;
@@ -2233,12 +2232,12 @@ yyreduce:
        symbol_list_destructor_set (list, (yyvsp[-1].code), (yylsp[-1]));
       symbol_list_free ((yyvsp[0].list));
     }
-/* Line 1429 of yacc.c  */
-#line 2238 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2237 "src/parse-gram.c"
     break;
 
   case 39:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 378 "src/parse-gram.y"
     {
       symbol_list *list;
@@ -2246,32 +2245,32 @@ yyreduce:
        symbol_list_printer_set (list, (yyvsp[-1].code), (yylsp[-1]));
       symbol_list_free ((yyvsp[0].list));
     }
-/* Line 1429 of yacc.c  */
-#line 2251 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2250 "src/parse-gram.c"
     break;
 
   case 40:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 385 "src/parse-gram.y"
     {
       default_prec = true;
     }
-/* Line 1429 of yacc.c  */
-#line 2261 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2260 "src/parse-gram.c"
     break;
 
   case 41:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 389 "src/parse-gram.y"
     {
       default_prec = false;
     }
-/* Line 1429 of yacc.c  */
-#line 2271 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2270 "src/parse-gram.c"
     break;
 
   case 42:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 393 "src/parse-gram.y"
     {
       /* Do not invoke muscle_percent_code_grow here since it invokes
@@ -2279,89 +2278,89 @@ yyreduce:
       muscle_code_grow ("percent_code()", (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 2284 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2283 "src/parse-gram.c"
     break;
 
   case 43:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 400 "src/parse-gram.y"
     {
       muscle_percent_code_grow ((yyvsp[-1].uniqstr), (yylsp[-1]), (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 2295 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2294 "src/parse-gram.c"
     break;
 
   case 44:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 414 "src/parse-gram.y"
     {}
-/* Line 1429 of yacc.c  */
-#line 2303 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2302 "src/parse-gram.c"
     break;
 
   case 45:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 415 "src/parse-gram.y"
     { muscle_code_grow ("union_name", (yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2311 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2310 "src/parse-gram.c"
     break;
 
   case 46:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 420 "src/parse-gram.y"
     {
       union_seen = true;
       muscle_code_grow ("stype", (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 2323 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2322 "src/parse-gram.c"
     break;
 
   case 47:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 431 "src/parse-gram.y"
     { current_class = nterm_sym; }
-/* Line 1429 of yacc.c  */
-#line 2331 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2330 "src/parse-gram.c"
     break;
 
   case 48:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 432 "src/parse-gram.y"
     {
       current_class = unknown_sym;
       current_type = NULL;
     }
-/* Line 1429 of yacc.c  */
-#line 2342 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2341 "src/parse-gram.c"
     break;
 
   case 49:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 436 "src/parse-gram.y"
     { current_class = token_sym; }
-/* Line 1429 of yacc.c  */
-#line 2350 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2349 "src/parse-gram.c"
     break;
 
   case 50:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 437 "src/parse-gram.y"
     {
       current_class = unknown_sym;
       current_type = NULL;
     }
-/* Line 1429 of yacc.c  */
-#line 2361 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2360 "src/parse-gram.c"
     break;
 
   case 51:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 442 "src/parse-gram.y"
     {
       symbol_list *list;
@@ -2370,12 +2369,12 @@ yyreduce:
        symbol_type_set (list->content.sym, (yyvsp[-1].uniqstr), (yylsp[-1]));
       symbol_list_free ((yyvsp[0].list));
     }
-/* Line 1429 of yacc.c  */
-#line 2375 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2374 "src/parse-gram.c"
     break;
 
   case 52:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 453 "src/parse-gram.y"
     {
       symbol_list *list;
@@ -2388,202 +2387,202 @@ yyreduce:
       symbol_list_free ((yyvsp[0].list));
       current_type = NULL;
     }
-/* Line 1429 of yacc.c  */
-#line 2393 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2392 "src/parse-gram.c"
     break;
 
   case 53:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 467 "src/parse-gram.y"
     { (yyval.assoc) = left_assoc; }
-/* Line 1429 of yacc.c  */
-#line 2401 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2400 "src/parse-gram.c"
     break;
 
   case 54:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 468 "src/parse-gram.y"
     { (yyval.assoc) = right_assoc; }
-/* Line 1429 of yacc.c  */
-#line 2409 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2408 "src/parse-gram.c"
     break;
 
   case 55:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 469 "src/parse-gram.y"
     { (yyval.assoc) = non_assoc; }
-/* Line 1429 of yacc.c  */
-#line 2417 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2416 "src/parse-gram.c"
     break;
 
   case 56:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 470 "src/parse-gram.y"
     { (yyval.assoc) = precedence_assoc; }
-/* Line 1429 of yacc.c  */
-#line 2425 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2424 "src/parse-gram.c"
     break;
 
   case 57:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 474 "src/parse-gram.y"
     { current_type = NULL; }
-/* Line 1429 of yacc.c  */
-#line 2433 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2432 "src/parse-gram.c"
     break;
 
   case 58:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 475 "src/parse-gram.y"
     { current_type = (yyvsp[0].uniqstr); tag_seen = true; }
-/* Line 1429 of yacc.c  */
-#line 2441 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2440 "src/parse-gram.c"
     break;
 
   case 59:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 481 "src/parse-gram.y"
     { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2449 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2448 "src/parse-gram.c"
     break;
 
   case 60:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 483 "src/parse-gram.y"
     { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0]))); }
-/* Line 1429 of yacc.c  */
-#line 2457 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2456 "src/parse-gram.c"
     break;
 
   case 61:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 487 "src/parse-gram.y"
     { (yyval.symbol) = (yyvsp[0].symbol); }
-/* Line 1429 of yacc.c  */
-#line 2465 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2464 "src/parse-gram.c"
     break;
 
   case 62:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 488 "src/parse-gram.y"
     { (yyval.symbol) = (yyvsp[-1].symbol); symbol_user_token_number_set ((yyvsp[-1].symbol), (yyvsp[0].integer), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2473 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2472 "src/parse-gram.c"
     break;
 
   case 63:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 494 "src/parse-gram.y"
     { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2481 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2480 "src/parse-gram.c"
     break;
 
   case 64:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 496 "src/parse-gram.y"
     { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0]))); }
-/* Line 1429 of yacc.c  */
-#line 2489 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2488 "src/parse-gram.c"
     break;
 
   case 65:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 500 "src/parse-gram.y"
     { (yyval.list) = (yyvsp[0].list); }
-/* Line 1429 of yacc.c  */
-#line 2497 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2496 "src/parse-gram.c"
     break;
 
   case 66:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 501 "src/parse-gram.y"
     { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), (yyvsp[0].list)); }
-/* Line 1429 of yacc.c  */
-#line 2505 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2504 "src/parse-gram.c"
     break;
 
   case 67:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 505 "src/parse-gram.y"
     { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2513 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2512 "src/parse-gram.c"
     break;
 
   case 68:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 506 "src/parse-gram.y"
     { (yyval.list) = symbol_list_type_new ((yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2521 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2520 "src/parse-gram.c"
     break;
 
   case 69:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 507 "src/parse-gram.y"
     { (yyval.list) = symbol_list_default_tagged_new ((yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2529 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2528 "src/parse-gram.c"
     break;
 
   case 70:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 508 "src/parse-gram.y"
     { (yyval.list) = symbol_list_default_tagless_new ((yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2537 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2536 "src/parse-gram.c"
     break;
 
   case 71:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 514 "src/parse-gram.y"
     {
        current_type = (yyvsp[0].uniqstr);
        tag_seen = true;
      }
-/* Line 1429 of yacc.c  */
-#line 2548 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2547 "src/parse-gram.c"
     break;
 
   case 72:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 519 "src/parse-gram.y"
     {
        symbol_class_set ((yyvsp[0].symbol), current_class, (yylsp[0]), true);
        symbol_type_set ((yyvsp[0].symbol), current_type, (yylsp[0]));
      }
-/* Line 1429 of yacc.c  */
-#line 2559 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2558 "src/parse-gram.c"
     break;
 
   case 73:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 524 "src/parse-gram.y"
     {
       symbol_class_set ((yyvsp[-1].symbol), current_class, (yylsp[-1]), true);
       symbol_type_set ((yyvsp[-1].symbol), current_type, (yylsp[-1]));
       symbol_user_token_number_set ((yyvsp[-1].symbol), (yyvsp[0].integer), (yylsp[0]));
     }
-/* Line 1429 of yacc.c  */
-#line 2571 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2570 "src/parse-gram.c"
     break;
 
   case 74:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 530 "src/parse-gram.y"
     {
       symbol_class_set ((yyvsp[-1].symbol), current_class, (yylsp[-1]), true);
       symbol_type_set ((yyvsp[-1].symbol), current_type, (yylsp[-1]));
       symbol_make_alias ((yyvsp[-1].symbol), (yyvsp[0].symbol), (yyloc));
     }
-/* Line 1429 of yacc.c  */
-#line 2583 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2582 "src/parse-gram.c"
     break;
 
   case 75:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 536 "src/parse-gram.y"
     {
       symbol_class_set ((yyvsp[-2].symbol), current_class, (yylsp[-2]), true);
@@ -2591,136 +2590,136 @@ yyreduce:
       symbol_user_token_number_set ((yyvsp[-2].symbol), (yyvsp[-1].integer), (yylsp[-1]));
       symbol_make_alias ((yyvsp[-2].symbol), (yyvsp[0].symbol), (yyloc));
     }
-/* Line 1429 of yacc.c  */
-#line 2596 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2595 "src/parse-gram.c"
     break;
 
   case 82:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 566 "src/parse-gram.y"
     {
       yyerrok;
     }
-/* Line 1429 of yacc.c  */
-#line 2606 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2605 "src/parse-gram.c"
     break;
 
   case 83:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 572 "src/parse-gram.y"
     { current_lhs = (yyvsp[-1].symbol); current_lhs_location = (yylsp[-1]);
     current_lhs_named_ref = (yyvsp[0].named_ref); }
-/* Line 1429 of yacc.c  */
-#line 2615 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2614 "src/parse-gram.c"
     break;
 
   case 85:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 577 "src/parse-gram.y"
     { grammar_current_rule_end ((yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2623 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2622 "src/parse-gram.c"
     break;
 
   case 86:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 578 "src/parse-gram.y"
     { grammar_current_rule_end ((yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2631 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2630 "src/parse-gram.c"
     break;
 
   case 88:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 584 "src/parse-gram.y"
     { grammar_current_rule_begin (current_lhs, current_lhs_location,
                                  current_lhs_named_ref); }
-/* Line 1429 of yacc.c  */
-#line 2640 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2639 "src/parse-gram.c"
     break;
 
   case 89:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 587 "src/parse-gram.y"
     { grammar_current_rule_symbol_append ((yyvsp[-1].symbol), (yylsp[-1]), (yyvsp[0].named_ref)); }
-/* Line 1429 of yacc.c  */
-#line 2648 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2647 "src/parse-gram.c"
     break;
 
   case 90:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 589 "src/parse-gram.y"
     { grammar_current_rule_action_append ((yyvsp[-1].code), (yylsp[-1]), (yyvsp[0].named_ref)); }
-/* Line 1429 of yacc.c  */
-#line 2656 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2655 "src/parse-gram.c"
     break;
 
   case 91:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 591 "src/parse-gram.y"
     { grammar_current_rule_prec_set ((yyvsp[0].symbol), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2664 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2663 "src/parse-gram.c"
     break;
 
   case 92:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 593 "src/parse-gram.y"
     { grammar_current_rule_dprec_set ((yyvsp[0].integer), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2672 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2671 "src/parse-gram.c"
     break;
 
   case 93:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 595 "src/parse-gram.y"
     { grammar_current_rule_merge_set ((yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2680 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2679 "src/parse-gram.c"
     break;
 
   case 94:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 599 "src/parse-gram.y"
     { (yyval.named_ref) = 0; }
-/* Line 1429 of yacc.c  */
-#line 2688 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2687 "src/parse-gram.c"
     break;
 
   case 95:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 601 "src/parse-gram.y"
     { (yyval.named_ref) = named_ref_new((yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2696 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2695 "src/parse-gram.c"
     break;
 
   case 97:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 613 "src/parse-gram.y"
     { (yyval.uniqstr) = uniqstr_new ((yyvsp[0].chars)); }
-/* Line 1429 of yacc.c  */
-#line 2704 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2703 "src/parse-gram.c"
     break;
 
   case 98:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 618 "src/parse-gram.y"
     { (yyval.chars) = ""; }
-/* Line 1429 of yacc.c  */
-#line 2712 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2711 "src/parse-gram.c"
     break;
 
   case 99:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 619 "src/parse-gram.y"
     { (yyval.chars) = (yyvsp[0].uniqstr); }
-/* Line 1429 of yacc.c  */
-#line 2720 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2719 "src/parse-gram.c"
     break;
 
   case 101:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 630 "src/parse-gram.y"
     {
       code_props plain_code;
@@ -2730,51 +2729,51 @@ yyreduce:
       gram_scanner_last_string_free ();
       (yyval.chars) = plain_code.code;
     }
-/* Line 1429 of yacc.c  */
-#line 2735 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2734 "src/parse-gram.c"
     break;
 
   case 102:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 650 "src/parse-gram.y"
     { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2743 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2742 "src/parse-gram.c"
     break;
 
   case 103:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 652 "src/parse-gram.y"
     {
       (yyval.symbol) = symbol_get (char_name ((yyvsp[0].character)), (yylsp[0]));
       symbol_class_set ((yyval.symbol), token_sym, (yylsp[0]), false);
       symbol_user_token_number_set ((yyval.symbol), (yyvsp[0].character), (yylsp[0]));
     }
-/* Line 1429 of yacc.c  */
-#line 2755 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2754 "src/parse-gram.c"
     break;
 
   case 104:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 660 "src/parse-gram.y"
     { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[0].uniqstr), (yylsp[0])); }
-/* Line 1429 of yacc.c  */
-#line 2763 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2762 "src/parse-gram.c"
     break;
 
   case 107:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 672 "src/parse-gram.y"
     {
       (yyval.symbol) = symbol_get (quotearg_style (c_quoting_style, (yyvsp[0].chars)), (yylsp[0]));
       symbol_class_set ((yyval.symbol), token_sym, (yylsp[0]), false);
     }
-/* Line 1429 of yacc.c  */
-#line 2774 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2773 "src/parse-gram.c"
     break;
 
   case 109:
-/* Line 1429 of yacc.c  */
+/* Line 1428 of yacc.c  */
 #line 681 "src/parse-gram.y"
     {
       code_props plain_code;
@@ -2784,15 +2783,26 @@ yyreduce:
       muscle_code_grow ("epilogue", plain_code.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
-/* Line 1429 of yacc.c  */
-#line 2789 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2788 "src/parse-gram.c"
     break;
 
 
-/* Line 1429 of yacc.c  */
-#line 2794 "src/parse-gram.c"
+/* Line 1428 of yacc.c  */
+#line 2793 "src/parse-gram.c"
       default: break;
     }
+  /* User semantic actions sometimes alter yychar, and that requires
+     that yytoken be updated with the new translation.  We take the
+     approach of translating immediately before every use of yytoken.
+     One alternative is translating here after every semantic action,
+     but that translation would be missed if the semantic action invokes
+     YYABORT, YYACCEPT, or YYERROR immediately after altering yychar or
+     if it invokes YYBACKUP.  In the case of YYABORT or YYACCEPT, an
+     incorrect destructor might then be invoked immediately.  In the
+     case of YYERROR or YYBACKUP, subsequent parser actions might lead
+     to an incorrect destructor call or verbose syntax error message
+     before the lookahead is translated.  */
   YY_SYMBOL_PRINT ("-> $$ =", yyr1[yyn], &yyval, &yyloc);
 
   YYPOPSTACK (yylen);
@@ -2821,6 +2831,10 @@ yyreduce:
 | yyerrlab -- here on detecting error |
 `------------------------------------*/
 yyerrlab:
+  /* Make sure we have latest lookahead translation.  See comments at
+     user semantic actions for why this is necessary.  */
+  yytoken = YYTRANSLATE (yychar);
+
   /* If not already recovering from an error, report this error.  */
   if (!yyerrstatus)
     {
@@ -2973,8 +2987,13 @@ yyexhaustedlab:
 
 yyreturn:
   if (yychar != YYEMPTY)
-     yydestruct ("Cleanup: discarding lookahead",
-                yytoken, &yylval, &yylloc);
+    {
+      /* Make sure we have latest lookahead translation.  See comments at
+         user semantic actions for why this is necessary.  */
+      yytoken = YYTRANSLATE (yychar);
+      yydestruct ("Cleanup: discarding lookahead",
+                  yytoken, &yylval, &yylloc);
+    }
   /* Do not reclaim the symbols of the rule which action triggered
      this YYABORT or YYACCEPT.  */
   YYPOPSTACK (yylen);
@@ -2997,7 +3016,7 @@ yyreturn:
   return YYID (yyresult);
 }
 
-/* Line 1639 of yacc.c  */
+/* Line 1658 of yacc.c  */
 #line 691 "src/parse-gram.y"
 
 

diff --git a/src/parse-gram.h b/src/parse-gram.h
index e5b88b76b05a4bb1a36e9faa9e269e6f31296f5e..17f86cde25cba131d07defa25b824008ebbb65a3 100644 (file)
--- a/src/parse-gram.h
+++ b/src/parse-gram.h
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 2.4.456-ea2e.  */
+/* A Bison parser, made by GNU Bison 2.4.457-4395a.  */
 
 /* Interface for Bison's Yacc-like parsers in C
 
@@ -31,7 +31,7 @@
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 /* "%code requires" blocks.  */
-/* Line 1640 of yacc.c  */
+/* Line 1659 of yacc.c  */
 #line 202 "src/parse-gram.y"
 
 # ifndef PARAM_TYPE
@@ -46,7 +46,7 @@
 # endif
 
 
-/* Line 1640 of yacc.c  */
+/* Line 1659 of yacc.c  */
 #line 51 "src/parse-gram.h"
 
 /* Tokens.  */
@@ -173,7 +173,7 @@
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
 {
-/* Line 1640 of yacc.c  */
+/* Line 1659 of yacc.c  */
 #line 88 "src/parse-gram.y"
 
   assoc assoc;
@@ -186,13 +186,13 @@ typedef union YYSTYPE
   uniqstr uniqstr;
   unsigned char character;
 
-/* Line 1640 of yacc.c  */
+/* Line 1659 of yacc.c  */
 #line 226 "src/parse-gram.y"
 
   param_type param;
 
 
-/* Line 1640 of yacc.c  */
+/* Line 1659 of yacc.c  */
 #line 197 "src/parse-gram.h"
 } YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1

diff --git a/tests/actions.at b/tests/actions.at
index d317920dc47505293fae23b080d5ac4e008224c9..144791c505c6662362ba4d381a2ead4d40d3ba67 100644 (file)
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -1408,3 +1408,74 @@ AT_MATCHES_CHECK([input.c], [[// TEST:Y:1 [;{}]*\n;\}$]],  [[12]])
 AT_MATCHES_CHECK([input.c], [[#define TEST_MACRO_N \\\n\[\]"broken\\" \$ \@ \$\$ \@\$ \[\];\\\nstring;"\}]], [[2]])
 
 AT_CLEANUP
+
+
+## -------------------------------------------------- ##
+## Destroying lookahead assigned by semantic action.  ##
+## -------------------------------------------------- ##
+
+AT_SETUP([[Destroying lookahead assigned by semantic action]])
+
+AT_DATA_GRAMMAR([input.y],
+[[
+%code {
+  #include <assert.h>
+  #include <stdio.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  #define USE(Var)
+}
+
+%destructor { fprintf (stderr, "'a' destructor\n"); } 'a'
+%destructor { fprintf (stderr, "'b' destructor\n"); } 'b'
+
+%%
+
+// In a previous version of Bison, yychar assigned by the semantic
+// action below was not translated into yytoken before the lookahead was
+// discarded and thus before its destructor (selected according to
+// yytoken) was called in order to return from yyparse.  This would
+// happen even if YYACCEPT was performed in a later semantic action as
+// long as only consistent states with default reductions were visited
+// in between.  However, we leave YYACCEPT in the same semantic action
+// for this test in order to show that skeletons cannot simply translate
+// immediately after every semantic action because a semantic action
+// that has set yychar might not always return normally.  Instead,
+// skeletons must translate before every use of yytoken.
+start: 'a' accept { USE($1); } ;
+accept: /*empty*/ {
+  assert (yychar == YYEMPTY);
+  yychar = 'b';
+  YYACCEPT;
+} ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+int
+main (void)
+{
+  return yyparse ();
+}
+]])
+
+AT_BISON_CHECK([[-o input.c input.y]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[0]], [],
+[['b' destructor
+'a' destructor
+]])
+
+AT_CLEANUP

diff --git a/tests/conflicts.at b/tests/conflicts.at
index 26ec08d4688403ef6ee39ef4bdc38321d0d17890..faaa3b9d5639c341ce9cc3f23ccfa31c8c448ac2 100644 (file)
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -139,6 +139,130 @@ AT_CLEANUP
 
 
 
+## ------------------------------------------- ##
+## parse.error=verbose and consistent errors.  ##
+## ------------------------------------------- ##
+
+AT_SETUP([[parse.error=verbose and consistent errors]])
+
+m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
+
+AT_BISON_CHECK([$1[ -o input.c input.y]])
+AT_COMPILE([[input]])
+
+m4_pushdef([AT_EXPECTING], [m4_if($3, [ab], [[, expecting 'a' or 'b']],
+                                  $3, [a],  [[, expecting 'a']],
+                                  $3, [b],  [[, expecting 'b']])])
+
+AT_PARSER_CHECK([[./input]], [[1]], [],
+[[syntax error, unexpected ]$2[]AT_EXPECTING[
+]])
+
+m4_popdef([AT_EXPECTING])
+
+])
+
+AT_DATA_GRAMMAR([input.y],
+[[%code {
+  #include <assert.h>
+  #include <stdio.h>
+  int yylex (void);
+  void yyerror (char const *);
+  #define USE(Var)
+}
+
+%define parse.error verbose
+
+// The point isn't to test IELR here, but state merging happens to
+// complicate the example.
+%define lr.type ielr
+
+%nonassoc 'a'
+
+// If yylval=0 here, then we know that the 'a' destructor is being
+// invoked incorrectly for the 'b' set in the semantic action below.
+// All 'a' tokens are returned by yylex, which sets yylval=1.
+%destructor {
+  if (!$$)
+    fprintf (stderr, "Wrong destructor.\n");
+} 'a'
+
+%%
+
+// The lookahead assigned by the semantic action isn't needed before
+// either error action is encountered.  In a previous version of Bison,
+// this was a problem as it meant yychar was not translated into yytoken
+// before either error action.  The second error action thus invoked a
+// destructor that it selected according to the incorrect yytoken.  The
+// first error action would have reported an incorrect unexpected token
+// except that, due to another bug, the unexpected token is not reported
+// at all because the error action is the default action in a consistent
+// state.  That bug still needs to be fixed.
+start: error-reduce consistent-error 'a' { USE ($3); } ;
+
+error-reduce:
+  'a' 'a' consistent-reduction consistent-error 'a'
+  { USE (($1, $2, $5)); }
+| 'a' error
+  { USE ($1); }
+;
+
+consistent-reduction: /*empty*/ {
+  assert (yychar == YYEMPTY);
+  yylval = 0;
+  yychar = 'b';
+} ;
+
+consistent-error:
+  'a' { USE ($1); }
+| /*empty*/ %prec 'a'
+;
+
+// Provide another context in which all rules are useful so that this
+// test case looks a little more realistic.
+start: 'b' consistent-error 'b' ;
+
+%%
+
+int
+yylex (void)
+{
+  static char const *input = "aa";
+  yylval = 1;
+  return *input++;
+}
+
+void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+  return yyparse ();
+}
+]])
+
+# See comments in grammar for why this test doesn't succeed.
+AT_XFAIL_IF([[:]])
+
+AT_CONSISTENT_ERRORS_CHECK([], [['b']], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=consistent]],
+                           [['b']], [[none]])
+
+# Canonical LR doesn't foresee the error for 'a'!
+AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=accepting]],
+                           [[$end]], [[a]])
+AT_CONSISTENT_ERRORS_CHECK([[-Flr.type=canonical-lr]], [[$end]], [[a]])
+
+m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
+
+AT_CLEANUP
+
+
+
 ## ------------------------- ##
 ## Unresolved SR Conflicts.  ##
 ## ------------------------- ##